Effects of Harvest-Aids on Seed Nutrition in Soybean under Midsouth USA Conditions

Abstract

Interest in using harvest aids (defoliants or crop desiccants) such as paraquat, carfentrazone-ethyl, glyphosate, and sodium chlorate (NaClO3) have become increasingly important to assure harvest efficiency, producer profit, and to maintain seed quality. However, information on the effects of harvest aids on seed nutrition (composition) (protein, oil, fatty acids, sugars, and amino acids) in soybean is very limited. The objective of this research was to investigate the influence of harvest aids on seed protein, oil, fatty acids, sugars, and amino acids in soybean. Our hypothesis was that harvest aid may influence seed nutrition, especially at R6 as at R6 the seeds may still undergo biochemical changes. Field experiments were conducted in 2012 and 2013 under Midsouth USA environmental conditions in which harvest aids were applied at R6 (seed-fill) and R7 (yellow pods) growth stages. Harvest aids applied included an untreated control, 0.28 kg ai ha−1 of paraquat, 0.28 kg ai ha−1 of paraquat, and 1.015 kg ai ha−1 of carfentrazone-ethyl (AIM); 6.72 kg ai ha−1 sodium chlorate, 1.015 kg ai ha−1 carfentrazone-ethyl; and 2.0 kg ae ha−1 glyphosate. Results showed that the application of harvest aids at either R6 or R7 resulted in the alteration of some seed composition such as protein, oil, oleic acid, fructose, and little effects on amino acids. In addition, harvest aids affected seed composition constituents differently depending on year and growth stage. This research demonstrated the possible alteration of some nutrients by harvest aids. This research helps growers and scientists to advance the understanding and management of harvest aids and investigate possible effects of harvest aids on seed nutrition.

Responses of seed yield, quality, and composition to the harvest‐aid paraquat in soybean grown in Mississippi

“…(2020), but both raffinose and stachyose increased, disagreeing with the results of Bellaloui et al. (2020). The disagreement of the findings could be due to differences in paraquat rates used, cultivars, planting dates, or locations (Valentine et al., 2017), as well as the amount and pattern of rainfall and heat in each year (Bellaloui et al., 2020) as biotic and abiotic factors can increase the severity and the stress response to paraquat.…”

“…Our results showed that sucrose decreased, agreeing with the results of Bellaloui et al. (2020), but both raffinose and stachyose increased, disagreeing with the results of Bellaloui et al. (2020).…”

“…A recent experiment was conducted to investigate the effects of paraquat (at a rate of 0.28 kg a.i. ha –1 ), carfentrazone‐ethyl, glyphosate, and sodium chlorate (NaClO 3 ) on seed protein, oil, fatty acids, sugars, and amino acids in soybean when defoliants were applied at the R6 (seed‐fill) or R7 (yellow pods) growth stages (Bellaloui et al., 2020). They found that the application of paraquat, paraquat + carfentrazone‐ethyl, NaClO 3 , and carfentrazone‐ethyl at R6 resulted in an increase of protein, but the application of carfentrazone‐ethyl or glyphosate resulted in higher oleic acid.…”

“…One can expect alteration of the carbon pathway as a result of paraquat application and the desiccation process. No previous information on the effects of paraquat on seed sugars is available, except for one recent study that showed a decrease in all sugars when paraquat was applied at R6 (Bellaloui et al., 2020). Our results showed that sucrose decreased, agreeing with the results of Bellaloui et al.…”

“…Information on the effects of paraquat on seed composition (protein, oil, fatty acids, and sugars) is scarce (Bellaloui et al., 2020), and what is available is either inconsistent or contradictory. Therefore, this information could be important in the future if a premium were paid at the delivery point for seed composition profile or if soybeans were used in seed production (Heatherly, 2018).…”